On spherically symmetric fields with dynamic torsion in gauge theories of gravitation

Within the framework of the Poincaré gauge field theory of gravity, the general gravitational Lagrangian coupled to the electromagnetic field is investigated. We treat the case of a static, spherically symmetric field with space reflection invariance. The exact solutions presented will be generated by a double-duality ansatz for the curvature. The Reissner-Nordström metric is singled out within a class of Lagrangians admitting an asymptotically flat metric.